Objection 1. It would seem that the production of the human body is not fittingly described in Scripture. For, as the human body was made by God, so also were the other works of the six days. But in the other works it is written, "God said; Let it be made, and it was made." Therefore the same should have been said of man.
Objection 2. Further, the human body was made by God immediately, as explained above (Article 2). Therefore it was not fittingly said, "Let us make man."
Objection 3. Further, the form of the human body is the soul itself which is the breath of life. Therefore, having said, "God made man of the slime of the earth," he should not have added: "And He breathed into him the breath of life."
Objection 4. Further, the soul, which is the breath of life, is in the whole body, and chiefly in the heart. Therefore it was not fittingly said: "He breathed into his face the breath of life."
Objection 5. Further, the male and female sex belong to the body, while the image of God belongs to the soul. But the soul, according to Augustine (Gen. ad lit. vii, 24), was made before the body. Therefore having said: "To His image He made them," he should not have added, "male and female He created them."
On the contrary, Is the authority of Scripture.
Reply to Objection 1. As Augustine observes (Gen. ad lit. vi, 12), man surpasses other things, not in the fact that God Himself made man, as though He did not make other things; since it is written (Psalm 101:26), "The work of Thy hands is the heaven," and elsewhere (Psalm 94:5), "His hands laid down the dry land"; but in this, that man is made to God's image. Yet in describing man's production, Scripture uses a special way of speaking, to show that other things were made for man's sake. For we are accustomed to do with more deliberation and care what we have chiefly in mind.
Reply to Objection 2. We must not imagine that when God said "Let us make man," He spoke to the angels, as some were perverse enough to think. But by these words is signified the plurality of the Divine Person, Whose image is more clearly expressed in man.
Reply to Objection 3. Some have thought that man's body was formed first in priority of time, and that afterwards the soul was infused into the formed body. But it is inconsistent with the perfection of the production of things, that God should have made either the body without the soul, or the soul without the body, since each is a part of human nature. This is especially unfitting as regards the body, for the body depends on the soul, and not the soul on the body.
To remove the difficulty some have said that the words, "God made man," must be understood of the production of the body with the soul; and that the subsequent words, "and He breathed into his face the breath of life," should be understood of the Holy Ghost; as the Lord breathed on His Apostles, saying, "Receive ye the Holy Ghost" (John 20:22). But this explanation, as Augustine says (De Civ. Dei xiii, 24), is excluded by the very words of Scripture. For we read farther on, "And man was made a living soul"; which words the Apostle (1 Corinthians 15:45) refers not to spiritual life, but to animal life. Therefore, by breath of life we must understand the soul, so that the words, "He breathed into his face the breath of life," are a sort of exposition of what goes before; for the soul is the form of the body.
Reply to Objection 4. Since vital operations are more clearly seen in man's face, on account of the senses which are there expressed; therefore Scripture says that the breath of life was breathed into man's face.
Reply to Objection 5. According to Augustine (Gen. ad lit. iv, 34), the works of the six days were done all at one time; wherefore according to him man's soul, which he holds to have been made with the angels, was not made before the sixth day; but on the sixth day both the soul of the first man was made actually, and his body in its causal elements. But other doctors hold that on the sixth day both body and soul of man were actually made.
Source: Summa Theologica (New Advent)